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BNE (northside) carb setup

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binner Fahrvergnugen

981 posts · joined Jan 2010 ·

#947284
well engine is running kinda, is anyone out there willing to help me out setting up a set of 40 IDF's with jet doctors ...got all my timing n such sorted out but be dammed if I can sync or tune these webers.Iit's running and idles ok but I seem to be getting some backfiring thru the muffler (unburnt gas,correct?) when its under load.
I have set timing at around 28 deg @3000 (009 dizzy) points are gapped correctly, no air leaks and everything is new.
Could this also be fuel psi related?

willing to pay in beers or similar.....

Cheers Binner
71 SQ

Sides Veteran Volks Folk

2,220 posts · joined May 2007 ·

#947287
What size engine with what size jets & venturi's ??? You sure no exhaust leaks ???

Backfiring often means lean, which suggests you're not at a good starting point with the jets rather than just balance issues.

Once you are at a good starting point, things I'd be doing in order are:
1. Fuel pressure (3.5 psi MAX).
2. Bench set carbs, balance & adjust linkage
3. Timing and point gap
4. Balance while running
5. Idle speed while running
6. Idle mix adjustment while running (lean best idle)
7 Repeat 4 through to 6 until a nice stable idle

Otherwise happy to take a few of those beers in a week or two if you're still having probs !!!
VWDCQ vice pres & web dude - vwdcqinc.org.au
Join a car club - get car peeps

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vassy66T1 Wow ... are U reading this?

2,120 posts · joined Jun 2003 ·

#947313
Give us engine and carb details i.e. capacity, cam, compression, exhaust (just as an idea what kind of motor it is) and carb details of venturis, idles, mains, emulsions etc.

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 ·

#947315
If it is a "bang" through the exhaust - my guess is rich

A "snap" or "sneeze" out the carbs - indicates lean

Idles I would start with 50's
vents are what they are - assuming you have a 2L or something, I would be expecting 32's
mains - 4.2X the vent = 135's
Airs - 180's
Mixture screws - 3 turns out

have a read here
http://www.aircooled.net/vw-carburetors-jetting-102/

and here

http://www.aircooled.net/synchronize-dual-vw-carburetors-103/
Futue te ipsum!!!

binner Fahrvergnugen

981 posts · joined Jan 2010 ·

#947398
2027cc
C35 cam
los panchito heads
40 idf webers, rebuilt, floats set as per weber specs
fuel is running at around 3psi
no leaks that i can find

i have installed the CB perf weber upgrade kit which includes the below

34 Venturis
1.80 Air Correction Jets
1.60 Main Jets


thanks for all the responses, I do appreaciate it

Cheers binner
71 SQ

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#947404
Ring me whilst your in front off your engine, if you'd like my help Ian.

No probs
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE

vassy66T1 Wow ... are U reading this?

2,120 posts · joined Jun 2003 ·

#947419
Idle jets??
Mains seam large to me.
Matt's offer is good👍

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 ·

#947443
160 is too large for 34's in my opinion and would be causing the backfire

140 or 145 would be better
Futue te ipsum!!!

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 ·

#947444
vassy66T1 wrote:Matt's offer is good👍
best offer you will get 👍
Futue te ipsum!!!

Bizarre Moderator The artist formerly known as blue74l

12,785 posts · joined Aug 2002 ·

#947448
does the upgrade kit have a spray bar instead of the normal set up??

cause that mucks things up for opinions on jetting - well it certainly did on my dells
you run a fatter main - so my opinion above may mean jack
Futue te ipsum!!!

binner Fahrvergnugen

981 posts · joined Jan 2010 ·

#947456
Bizarre wrote:does the upgrade kit have a spray bar instead of the normal set up??

cause that mucks things up for opinions on jetting - well it certainly did on my dells
you run a fatter main - so my opinion above may mean jack
spray bar and they supply you with new jets to fit, I put these in the last set of webers I rebuilt (40 IDFs) on a 1641 engine and they were fine. I was running this with electronic ignition and standard coil too.

**N E W S F L A S H**

I may be getting somewhere, the points (brand new) are already pitted after only running for about 1.5 hrs in total. I replaced them with new ones and it ran sweet for about 10/15 mins then started backfiring so I took out the points and BAM pitted to high hell.
I'm running a mallory MSD blaster 2 with a ballast resistor and standard 009 points dizzy. Maybe this is not the setup to use with standard points, anyone?

zapzap
71 SQ

binner Fahrvergnugen

981 posts · joined Jan 2010 ·

#947457
matberry wrote:Ring me whilst your in front off your engine, if you'd like my help Ian.

No probs
thanks fella, I'll keep persisting until I'm spent 🥲 then will give you a call when I'm knackered. 😂
71 SQ

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#947463
No worries, sounds like it could be rich with the 160's if it's not ignition
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE

binner Fahrvergnugen

981 posts · joined Jan 2010 ·

#947853
ok, so I swapped the coil for a 3 ohm standard coil and B A M ! it runs perky!!!!! (yeah I'm a crack head) I bought all this gear so long ago I can't remember whats what, so I just went ahead and shoved in the master blaster coil for electronic ig only which I was going to purchase but instead for some dumb reason I bought a points dizzy and just installed it without thinking and hence it was running like shit!!!.
So all I need now is to actually sync the carbs and I'm there. Been tearing round the neighbour hood all arvo and its running nice, just fine tuning now.

also had TACH BOUNCE so I installed a 1 amp diode inline and now it reads fuggin perfect!!! i likr it when things work 😁

Thanks for all the replies and I'm just glad it's almost ready for rego 😀
71 SQ

tar76 Custom Title Time!

1,622 posts · joined Dec 2009 ·

#947855
Nice man!
"Obey your Dreams"!


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65 11 wnd Split "The Cross".
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h fractals - an ever changing lifestyle

7,671 posts · joined Feb 2005 ·

#947864
good to hear mate 👍

n matt your mood script is gay.. xxx
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binner Fahrvergnugen

981 posts · joined Jan 2010 ·

#948188
ok ,so now a step further...pulled out the EMPI fuel pump (noisy) and bought one of these http://www.fuelflow.co.nz/FF_cms_03/eshop?page=shop.product_details&flypage=flypage.tpl&product_id=73 and one of these http://www.ebay.com.au/itm/Mallory-Ignition-4309-Aluminum-Fuel-Pressure-Regulator-3-12-psi-MAL4309-/360599632557?pt=Race_Car_Parts&hash=item53f569baad

3 year warranty, super quiet pump, mallory reg with bypass getting bang on 3.5 psi and able to adjust up to around 4 if needed. So after all that it finally runs nice and now just gotta get some help on the fine tuning and synching. Is it really worth buying a snail sync to tune or is a piece of pipe and good ears just as good?

cheers Binner
71 SQ

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#948189
i don't ecommend a snail, thee is usually no gasket between the elocity stack and ai-ilte bottom plate so it is meaningless imO. Just get each cylinde esponding the same to idle mixtue adjustment and you'll be in sync.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE

binner Fahrvergnugen

981 posts · joined Jan 2010 ·

#948405
matberry wrote:i don't ecommend a snail, thee is usually no gasket between the elocity stack and ai-ilte bottom plate so it is meaningless imO. Just get each cylinde esponding the same to idle mixtue adjustment and you'll be in sync.
i figured they would be a bit of a waste, I kinda trust my ears more but I am going a bit tone deaf so we will see 😂

So I am right in saying that I am bringing the highest down to the lowest, is this correct?
Is this sequence correct?

1> throttle linkages off
2a > idle screw just touching then dialed in 1 turn
b> mix screws dialled in to just touching then turned out 2.5 turns
3> set at static timing and adjust barrels with 12.5 mm hose pipe n tone deaf ear (car running obviously)
4> reattach linkages and make sure they move in synch
5> set 009 30-32 BTDC @3500 REVS
6> let it fall to wherever and note BTDC @ idle 900+/- REVS
7> fine tune timing on the road
8> pour a Sailor Jerry and sit back thinking about how much money has been spent on the project 🤪


Just fitted electronic ignition too so lets see how that goes.....
71 SQ

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#948408
^^ yep, my version

2a. 1/2 turn on idle stop screw
b. 1 3/4 turn for the mixture
3 adjust carbs using mixture screws to also help with balance, as you said, screw that makes most difference down idle speed or up other carb depending on where the speed is at first.
8 Bundy not SJ
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE

binner Fahrvergnugen

981 posts · joined Jan 2010 ·

#948432
matberry wrote:^^ yep, my version

2a. 1/2 turn on idle stop screw
b. 1 3/4 turn for the mixture
3 adjust carbs using mixture screws to also help with balance, as you said, screw that makes most difference down idle speed or up other carb depending on where the speed is at first.
8 Bundy not SJ
unkzzzz maaate... im on it this weekend, I may just make it to Al's open day.....😎
71 SQ